Mandrel



Feb. 27, 1934. A. o. ABBoT-r, JR

MANDREL Filed July l1 new INVENTOR Patented F eb. 27, 1934 PATENT OFFICE MANDREL Adrian 0. Abbott, Jr., Detroit, Mich., assignor to Morgan & Wright, Detroit, Mich., a. corporation of Michigan Application July 11, 1930. Serial No. 467,252

`1o claims.

My present invention relates to mandrels and more particularly to an improved iiexible mandrel for manufacturing endless latex tubes.

, Heretofore mandrels used in the manufacture -of endless latex tubes have comprised a plurality of metallic sections and with the construction employed it has been extremely difiicult to remove the formed tube from the mandrel. Particularly is this true when the endless tube is of small rim diameter.

With a view to obviate the objections to prior apparatus of this kind, I have designed the subject matter of the present invention and in carrying out my invention I utilize a flat annulus of resilient material split from its inner to its outer diameter on a line extending at an angle to the diameter of the annulus. This split portion is thus biasly arranged with respect to a `diameter of the annulus and in this split portion 20 is a connection adapted to bring the split ends together to form an endless mandrel. The outer surface of the annulus is provided with a network of channels and coated with material to .form a filter medium in order that the rubber a? 'particles may be deposited thereon when vacuum is applied within the structure of the annular member.

The principal object of my invention, therefore.

. is an improved mandrel for use in the manufacture of endless tubes.

Another object of my invention is an improved exible mandrel for manufacturing endless tubes of small rim diameter. A further object of my invention is an improved flexible mandrel of annular form and split and which facilitates the separation of the mandrel and endless tube.4

In the accompanying drawing is illustrated a 0, preferred embodiment of my invention:

Figure 1 is a side elevation partly in section showing the complete mandrel.

Fig. 2 is a cross section View on the line 2-2 of Fig. 1.

5. Fig. 3 is a cross sectional end View illustrating the mandrel in bent position to enable removal of the connector pin.

Fig. 4 is a fragmentary sectional view on the line 4 4 of Fig. 1, and Fig. 5 is a fragmentary and illustrating the method of separating the tube from the mandrel.

Referring to the drawing 10 designates the main body of the mandrel in the form of a flat G85 annulus, such body having a parting line 11 exview of the mandrel and tube formed thereon,l

tending nonradially from the inner to the outer diameter. The body 10 is composed of iiexible material, preferably rubber. in the body 10, on one side o the parting line il. and adJacent to the outer diameter is formed a recess 12 in which 60 fitted a metallic member 13. This member 13 1s provided with a plurality ci' periorations 14 and through which extend part ci' the material of the body 10 for holding the metallic member firmly in position. The metallic member 10 is provided 65 with a socket or cut-out portion 15 to receive the locking tongue 16 formed integral with a metallic member 17 located adjacent to the outer diameter ci the body l()V and on the other side of the parting line 11 from the metallic member 70 17. This metallic member 17 is provided with a plurality of periorations 18 through which the material of the body 10 extends to hold the metallio member 17 in position. The metallic member 17 is drilled and tapped to receive a perforat- 75 ed plug i9 and the threaded end of a tubular connector rod 20 for a purpose to be hereinafter described.

In the body member 10, adjacent to the inner diameter thereof and on the same side of the 80 parting line 11 as the metallic member 13 is embedded a metallic member 21 similar in outer construction with the metallic member 17. The member 21, however, is drilled to receive as a rotating and sliding t, the tubular connector 55 member 20. The member 21 is provided with a locking portion 22 similar to the locking portion 16 of the metallic member 17 and this locking member cooperates with a cut-out portion 23 of a member 24 embedded in the body 10 adjacent 90 to the inner diameter and on the opposite side of the parting line 11 from the member 21. The end surfaces of the body 10 which, when placed together form the parting line 11, are recessed to form cavities 25 for a purpose to be hereinafter 95 described.

The tubular connector member 20 at the end remote from the threaded end that engages with the drill and tapped portion of the metallic member 17 is provided with an enlargement 26 against 100 which rests Aa washer 27, and which conforms generally to the shape of the inner diameter of the member 10. Adjacent to the enlargement 26 is an enlargement 28 adapted to receive a pipe fitting 29 and by means of which the tubular con- 105 nector member 20 may be connected Vto a source of vacuum. Intermediate the ends of the tubular connector member 20 are circumferential grooves 30 and 31, the body of the tubular connector member 20 being provided at the grooved portion 30 and 31 with perforations 32 connecting such grooves with the interior of the tubular connector member. Assuming the normal operating position of the tubular connector with respect to the mandrel 10 to be shown in Fig. 2, then it will be seen that the circumferential grooves 30 and 31 in such tubular connector member 20 are in alignment with perforations 33 in the man'- drel 10 and which perforations extend outward to the surface of such mandrel.

The body of the mandrel 10 is, as stated above, of flexible material and preferably rubber and the outer surface thereof is knurled or has attached thereto by cementing or in any other suitable manner a rubber covering 34 that in turn has its outer surface knurled as indicated at 35. The knurling 35 forms a network of pasmil sages that extends all over the outer surface of the body 10 and such knurling 35 is connected with the passages 33 in the body of the mandrel 10, and also it will be noted that the plug 19 has a passage 36 therethrough which connects with the knurling 35. Over the knurling 35 is placed a fabric sleeve 37 which completely encloses the knurled material 34 and the ends of the sleeves are fitted into or tucked into the depressions 25 in the end surfaces of the member 10. In practice, there is deposited on the fabric 37 a covering of chalk or whiting 38 and a deposition of latex 39 to form the endless tube.

Assuming the mandrel 10 with its tubular connector member 20 to be constructed, as above described, and that the fabric sleeve 37 is fitted thereon, the ends tucked into the depressions 35,

`the washer 27 placed in position and the abutting ends of the mandrel 10 brought together by the connector 20. The operator will, by attaching a source of vacuum supply to the pipe fitting 29, dip the entire assembly into a solution `of clay or chalk, turn the vacuum into the mandrel 10 and there will be deposited a thin coating of clay or chalk on the surface of the fabric. This dipping operation requires but a few seconds, after which the clay or chalk coating is permitted to dry. The mandrel is now ready for the vacuum consists almost entirely of the rubber globules together with a small amount of absorbed non-rubbers.

The filtrate drawn from the treated latex is serum free from rubber and this filtrate or serum passes through the filter medium along the network of grooves formed by the knurling 35 through the openings 33, 36, holes 32, tubular connector member 29, and is removed from the system by vacuum. After several minutes of immersion or until the proper thickness of rubber 39 is obtained, the mandrel 10 is removed from the tank and the rubber coating 39 permitted to partially dry with the vacuum still applied at the pipe fitting 29. When the deposited rubber tube 39 is dried suinciently to maintain its ovvn form, the vacuum is removed from the pipe fitting 29 and the tube and mandrel are subjected to an elevated temperature sufiicient to drive off any remaining moisture and also to complete vulcanization of the tube 39. After vulcanization, the

latex tube 39 is removed manually from the mandrel 10 and to accomplish this, the tubular connector member 20 is loosened, and removed together with the washer 27. The function of the resilient material of which the body 10 is composed will now be apparent, as on account of the small rim diameter of the latex tube 39, it is necessary to bend or flex tlie mandrel 10 in the manner shown in Fig. 3, in order to permit removal of the tubular connector member 20.

With the removal of such connector tube, the opposing ends of the mandrel 10 assume the position in Fig. 5. The distance between the opposing ends may be increased within reason and the hole in the latex tube 39, caused by the presence on the mandrel of the washer 27, is stretched over the end of the mandrel as illustrated in Fig. 5. To further facilitate the separation of the mandrel 10 and endless latex tube 39, an air hose may be inserted into the tube opening at a point such as illustrated, for example, by the arrow 40 in Fig. 5. Air pressure is applied to the air hose and thereby iniiates the latex tube 39 to a greater external volume than that occupied by the man-4 drel with the result that the latex tube 39 is in a condition to be more easily removed therefrom. In the removal operation, the air hose is preferably held in the place as the arrow indicates, and is followed around with the tube 39 as the tube is progressively forced around the mandrel l0, until the entire mandrel is emerged through the connector opening of the tube 39.

After the tube 39 is removed the tube opening returns to its normal size, the tube is washed to remove any of the clay or chalk 37 that may have adhered to the interior of the tube, and such tube is then ready for the application of the valve base and valve stem. It is noted that the hole in the tube 39 made by the washer 27 is in such location that upon completion of the tube 39, such hole is covered by the base for the valve stem. After removal of the latex tube 39 from the mandrel 10, such mandrel is again assembled, as shown in Figs. 1 and 2, and is ready to be used again in a similar cycle of operation as above described.

I have described my invention as being preferably adapted to facilitate the manufacture of endless tubes from latex or an aqueous dispersion of rubber, either natural or artificial. It is obvious, however, that my invention is not to be so limited, and therefore, it is Within the scope of my invention to utilize my improved articulated mandrel to facilitate the manufacture of endless tubes by alternately dipping the same into a body 130 of latex or an aqueous dispersion of rubber, either natural or artificial, or I may dip the mandrel into. a suitable coagulant and then dip it into a body of latex or an aqueous dispersion of rubber, either natural or artificial until the requisite thickness of material is deposited thereon. Further, I am not limited to the use of latex, or an aqueous dispersion of rubber, either natural or artificial, but may utilize any coating material desired, in liquid or semi-liquid form. Further the knurling on the surface of the mandrel, and also the fabric cover, may be dispensed with where the desired endless tube is to be made by dipping.

Having thus described my invention, what I claim and desire to protect by Letters Patent is: 345

1. An improved mandrel for facilitating the manufacture of endless tubes by deposition from latex, comprising a length of resilient material, having its ends cut on an angle, formed into an annulus and with the cut ends abutting, means. 150'.

for locking the biased endstogether to form thereby an endless mandrel, a multiplicity of shallow channels formed on the surface, a ltering medium applied to the surface of the mandrel, and means for applying a differential pressure to the filtering medium.

2. An improved mandrel for facilitating the manufacture of endless tubes comprising a length of flat flexible material having cut ends formed into a flat annular member, means for locking the cut ends together to form the member into an endless mandrel, a multiplicity of channels formed on the surface of the mandrel, a filtering medium applied to the surface of the mandrel, and means for applying a differential pressure to the filtering medium.

3. An improved mandrel for manufacturing endless tubes comprising an annulus of resilient material, split from its internal to its external diameter on a chord, means for locking the annulus at the split to form an endless annular mandrel, a multiplicity of channels formed on the surface of the mandrel, a filtering medium applied to the surface of the mandrel, and means for applying a differential pressure to the filtering medium.

4. A hollow perforated annular filtering mandrel of resilient bendable material having relatively movable circumferentially overlapping end portions and a hollow locking pin extending into said end portions and constituting a gaseous passageway communicating with the hollow interior of the mandrel.

5. An annular mandrel of resilient bendable material having relatively movable end portions meeting in a non-radial plane, a retractable pin extending from outside of the mandrel into said end portions for holding them together, a multiplicity of channels formed on the surface of the mandrel, a filtering medium applied to the surn face of the mandrel, and means for applying a differential pressure to the filtering medium.

6. An annular mandrel of resilient bendable material having relatively movable circumfer- `entially overlapping ends, a locking pin extending into said ends and projecting from the inner periphery of said mandrel, a multiplicity of channels formed on the surface of the mandrel,

a filtering medium applied to the surface of the mandrel, and means for applying a differential pressure to the filtering medium.

7. An annular mandrel of resilient bendable material having relatively movable circumferentially overlapping end portions and a hollow locking pin extending into said end portions, a multiplicity of channels formed on the surface of the mandrel, a filtering medium applied to the surface of themandrel, and means for applying a differential pressure to the filtering medium.

8. An annular mandrel of resilient bendable material having relatively movable circumferentially overlapping end portions, a retractable pin extending into said end portions, means on one of said end portions cooperating with complementary means on said pin for securing the pin in place, a multiplicity of channels formed on the surface of the mandrel, a filtering medium applied to the surface of the mandrel, and means for applying a differential pressure to the filtering medium.

9. An improved mandrel for facilitating the manufacture of endless tubes of relatively small internal diameter, comprising a perforated hollow annulus of resilient bendable material split from its internal to its external diameter, and means comprising a hollow pin located along the inner periphery of said annulus for locking it 105 at the split part to form an endless mandrel, the length of said pin being at least equal to or greater than the diameter of the inner periphery of the mandrel, whereby said annulus may be bent to facilitate removal of said pin. 11g

1f). An annular mandrel of resilient bendable material having relatively movable end portions, inserts of relatively rigid material carried by said end portions, a locking pin extending into certain of said inserts, a multiplicity of 11,5 channels formed on the surface of the mandrel,

a filtering medium applied to the surface of the mandrel, passageways in said mandrel and along said pin in communication with said channels, and means for applying a differential pressure 120 to said filtering medium.

ADRIAN O. ABBOTT, JR. 

